1. Field of the Invention
The present invention pertains to an apparatus for removing accumulations of sand and similar sediments from process separator vessels by circulating vessel liquid through a pump and cyclone type separator and returning the liquid to the vessel.
2. Background
Certain fluid separation processes result also in the separation of solids which tend to accumulate in the process separator vessels. For example, in the production of crude oil and natural gas from subterranean wells the production stream is subjected to a separation process by passing the stream into and through a separator vessel wherein water and other more dense liquids are separated from the crude oil and/or gas. Crude oil production streams often contain large amounts of relatively fine sediments or sand which accumulate in the primary separator vessels and must be removed from time to time.
Typical separator vessels include a weir or dam for holding back the separated water or other more dense liquid from remixing with the separated crude oil, both streams being passed out of the vessel at a controlled rate so as to maintain liquid levels in the vessel to effect continuous operation of the process. Any disturbance of the process such as due to the injection of a cleanout liquid tends to unbalance the process flow rates and require frequent adjustment of the flow rates of the stream flowing into the vessel as well as the separated fluid streams leaving the vessel. This type of vessel cleanout process is difficult to manage and the equipment requirements for handling the evacuation of liquid as well as the quantity of liquid which inevitably accompanies the outflow of sediments must be substantial. Still further problems associated with the conventional solids removal systems pertains to the handling of the evacuated solids. Typically, the evacuation liquid with entrained solids leaving the process vessel is transferred to a separate separator vessel to allow the solids to settle and the liquid is then decanted and transferred back to the system or otherwise treated separately for disposal. However, environmental restrictions often limit the choices for disposal of the solids evacuation liquid. Accordingly, there has been a substantial need for improvements in systems for evacuating solids such as sand and similar sediments which accumulate in oil and gas separator vessels, in particular.